In many cases, a craftsman is required to fit a series of screws in a workpiece, but must pre-drill tap holes in the workpiece to enable rapid and true driving of the screws. This necessity occurs frequently in woodworking, for example in fixing molding around a door, assembling cabinetry, or hanging a door. Sheet metal workers also must pre-drill screw holes essentially every time a piece of sheet metal is affixed to backing with screws, for example when installing a metal roof. Tap holes are also drilled in plastic, plaster and other materials of construction prior to setting of screws. In some cases, when it is important to have the head of the screw flush with or slightly below the surface of the workpiece, a power tool may be used, either instead of, or in addition to, the tap hole drill.
In practice, as a craftsman moves along a workpiece, it is necessary for him to first drill (or countersink) a tap hole, and then drive the screw; then he moves to an adjacent location and repeats the drill/screw sequence. He must either repeatedly change the bit in the power tool from drill bit to screwdriver bit, or he must have two, or, if a countersink is to be used in addition to the drill bit, three power tools, each equipped with a different bit. In many cases, it is not convenient to have multiple power tools, and the constant changing of the bits is unduly time consuming and burdensome.
To overcome the problem of using many tools, there are many devices employed for removably securing a tool implement to a tool body or drive mechanism. These devices usually involve threadably interlocked adapter parts or devices which secure the tool implement with set screws, or the like, to the tool body. While these means are effective in accomplishing the ultimate result of securing the tool implement, they are not ideal, for a relatively large amount of time is lost and skill is necessary to properly engage and disengage these adapter devices. That is, it is often necessary for even the most dexterous person to use two hands to remove or attach the tool implement. Also, separate tools, some made especially for the adapter device, may be necessary to properly engage and disengage these devices.
Moreover, such conventional adapter devices do not firmly lock to the tool body and often become uncoupled from the tool body during use. For instance, conventional adapter devices often become uncoupled from the tool body when the adapter device is coupling a drill bit to the tool body which is to be used to drill wood. Drill bits often become bound up in the wood workpiece, resulting in the adapter device uncoupling from the tool body. This can result in significant down time to unbind the adapter device from the workpiece and again couple it to the tool body.
A need has arisen for a power tool adapter which can be quickly connected and disconnected to a power driven rotary bit in a simple and efficient manner with a single hand and yet firmly lock the adapter to the power driven bit. Such an adapter would allow a craftsman to easily change working bits with a single hand in workplaces, such as on the top of a ladder, where it is difficult to use two hands to make the necessary working bit change without fear of the adapter becoming uncoupled from the bit.
The present invention resulted from the inventors' observation of these problems, and their successful efforts to solve them. The present invention, therefore, is directed toward a power tool adapter which can be quickly connected and disconnected to a power-driven rotary bit with a single hand.